1. Field of the Invention
This invention is a container and, more particularly, it is directed to a container having a body made of resilient plastic material and a removable plastic cover sealed thereto.
2. Description of the Related Art
Containers made of plastic are known to the art. They possess many advantages over paper, wood or metallic containers, particularly when packaging materials such as resins or liquids.
In the past, it was common practice to ship resins, such as polytetrafluoroethylene resin, in fiber or paperboard containers or drums with a moistureproof gasket in the lid, generally made of metal, to prevent moisture absorption by the product. More recently, the design of this drum has been modified to incorporate a plastic liner or plastic foil barrier in the sidewall. In addition, the cover or lid design has been changed to a high density polyethylene construction to replace the varnished or lacquered lid.
These changes have improved the container but did not solve certain basic problems such as moisture absorption through the drum sidewall during periods of high humidity, sidewall fatigue, rust on the drum chimes and locking band, and gasket material adhering to the metal chimes. All of these factors have contributed to the deterioration and contamination of the resin packaged in the drum.
The use of an all-plastic container for packaging resins or similar materials has eliminated all or most of these problems; however, the designs have been complex and the mating rim/closure configurations required for proper closure have been such as to make it difficult to pour the contents from the container and, frequently, because of the surface configurations, material is left on portions of the rim or container sidewall after pouring. Additionally, in such designs, the cover is sometimes difficult to seal to avoid moisture problems or to reseal when all the resin is not immediately used, or when the container is used again. This has presented a challenge to the packaging arts and many attempts, and many designs, have evolved to solve these and other problems.
A typical solution of the closure problem is seen in U.S. Pat. No. 3,519,163 to Bardell which shows a "snap-on" closure for a plastic container having a U-shaped channel adapted to fit over the open end of the side wall structure and having an interlocking bead to hold it in place on the container. Another tapered bead is molded into the apex of the channel or a separate resilient sealing gasket is positioned in such apex to resiliently contact the open end of the container when the closure is applied in order to effect a fluid-tight seal between the closure and container. Other sealing arrangements such as tubular gaskets, flowed-in gaskets, and the like may also be provided within the channel in order to effect a fluid-tight seal between the closure and the container body. The walls of the channel are in contact with the inner and outer surfaces of the side wall structure and the inner wall of the channel projects into the container body when the closure is in place. The upper rim of the side wall is curved and presents a surface on which the U-shaped channel rests.
Another similar container of the prior art is seen in U.S. Pat. No. 3,474,928 to Hurtt which also shows a "snap-on" cover with a frusto-conically shaped surface defining an acute angle with a locking surface on the side wall of the container to permit the cover to be easily removed. The cover has a shoulder extending into the container and in contact with the inner surface of such container. The top of the container rim is flat.
U.S. Pat. No. 3,664,544 to Hammes shows still another all-plastic container in which a strap is used to urge a sealing gasket confined within an annular rim portion of the cover into contact with an annular section or extension of the wall of the body portion of the container to seal the cover to the body portion. The design is complex and the annular section of the body portion curves in an S-shape over the opening of the container.
The containers of these patents, while effective for many uses, in one particular or another, fail to meet all of the needs of a container for packaging materials, such as resins, which require very careful handling.
As an example, it is important when packaging resins, or other materials, to prevent contact by the cover which would "shear" or "smear" the resin particles. This could occur if residual particles remain on the lip or rim of the container after the resin is poured out of the container and the lid or cover replaced. Further, particles might become entrapped between a portion or extension on the cover which extends into the container and abuts the inner surface of the container, as shown in the Hurtt and Bardell patents discussed above, for example, and cause the same problem. And the rim design should be such as to minimize the presence of particles on their surface after pouring. If the rim surface is of the type shown in the prior art this, too, presents a major problem. And, of course, the container must also be easy to pour with no material caught on the body extension. This latter problem is particularly evident in the Hammes container discussed above.
This invention solves the problems of the prior art by providing an all plastic container having a novel inverted V-shaped rim extending outwardly from the opening of the container body, which makes it easy to pour material from the container and which rim is angled so that any residual particles remaining on their surface will slide off and, hence, present no problems of "shear" or "smear" when the cover is replaced. The cover, in turn, has a mating V-shaped surface into which the rim fits for easily and properly positioning the cover on the container. The cover also has a pocket containing a sealing ring or gasket and a locking strap is provided to urge this ring into sealing contact with a surface of the rim to form a novel sealed container.